Floor coverings

ABSTRACT

Resilient floor coverings are disclosed wherein the wear layer is a polymer composition, prepared from an ionomer resin and a polyfunctional olefinic compound, such as a polyfunctional acrylate. These floor coverings have good visual appearance and good burn, abrasion and stain resistance.

TECHNICAL FIELD

This invention relates to resilient floor coverings and to methods ofmaking such floor coverings.

BACKGROUND ART

Resilient flooring coverings, which include for example vinyl tiles andvinyl sheet, are well known. They are described for example in anarticle entitled "Flooring Materials" in Encyclopedia of Polymer Scienceand Engineering, Wiley-Interscience, Volume 7 (1987), pages 233-247.Such floor coverings, as described in that article, are compositematerials which comprise a transparent or translucent wear (upper)layer, a decorative layer such as a printed patterned layer and one ormore backing (lower) layers. The wear layer of a resilient vinyl floorcovering according to that article consists of a plasticised PVCcomposition. The printed patterned layer may for example be a printedacrylic or PVC film. The backing layer adjacent such a printed patternedlayer commonly contains one or more white or other coloured pigments toenhance the appearance of the printed patterned layer as seen throughthe wear layer, and this type of backing layer may be called a face ply.Such composite floor coverings are commonly laminates, the compositionof each layer in the laminate being chosen so as to provide a desiredbalance of physical properties both in that layer and in the floorcovering as a whole. Resilient floor coverings are also known whichcomprise a decorative, for example pigmented, opaque vinyl wear layerlaminated to one or more backing layers.

Vinyl floor coverings have enjoyed considerable commercial success butsuffer from a number of disadvantages. Plasticised PVC is slightlyyellow in colour, and it tends to become more yellow on exposure to theamounts of UV light normally occurring in interior environments. Theclarity and visual appearance of a plasticised PVC wear layer and thevisual appearance of a decorative layer such as a printed patternedlayer through a transparent or translucent wear layer are therefore notas good as could be desired. The resistance of vinyl floor coverings towear, abrasion, scratching and scuffing is not as great as could bedesired. Vinyl floor coverings are marred by exposure to heat, forexample lit cigarettes. The use of vinyl floor coverings has beenobjected to on environmental grounds, both in that they contain thechlorinated polymer PVC and in that they contain volatile organiccompounds as plasticisers.

JP-A-56-073,178, JP-A-57-015,922 and GB-A-2,120,266 describe methods ofmanufacturing floor coverings in which a PVC composition comprising apolyfunctional monomer is formed into a wear layer which is then exposedto ionising (electron beam) radiation to induce crosslinking. Such floorcoverings are said to exhibit improved cigarette burn resistance.

Ionomer resins which are thermoplastic copolymers based on an olefin andan alpha, beta-unsaturated carboxylic acid are well-known. They aredescribed for example in an article entitled "Ionic Polymers" inEncyclopedia of Polymer Science and Engineering, Wiley-Interscience,Volume 8 (1987), pages 393-423. They are available commercially, forexample from Du Pont under the Trade mark "Surlyn". Many grades of suchresins are available commercially.

U.S. Pat. No. 4,083,824 states that the use of such ionomer resins inflooring compositions is severely restricted since they generally havedisadvantageously low use temperatures and display extensive creepaccompanied by a rapid decrease in modulus at normal room temperatures.Processing problems using ionomer resins are said to be severe due totheir great tenacity for metal surfaces. U.S. Pat. No. 4,083,824discloses a non-vinyl surface-covering composition comprising (a) amineral filler dispersed throughout a binder comprising (b1) a copolyblock acrylate and (b2) an ionomer resin. The weight ratio of thecomponents (a), (b1) and (b2) disclosed in that reference is in therange 8-32:32-8:60 to 3-12:12-3:85.

GB-A-2,019,315 describes a method for making a dimensionally stabledecorative floor covering in which a heated mass of thermoplasticmaterial is hot calendered to form a sheet which is deposited on aconveyor. The sheet and conveyor are then heated, a pattern is depositedon the sheet from a preprinted transfer paper, a clear wear layer whichmay be of an ionomer resin is laminated over the pattern, and thesurface of the wear layer is embossed by passage over engraved rollers.The resulting composite floor covering is cooled, stripped from theconveyor and cut into tiles which are then annealed.

U.S. Pat. No. 4,333,981 discloses an animal stall floor and wallcovering which comprises a laminate of (a) a liquid-impermeable layer ofan ionomer resin at least 125 micron (5 mil) thick superimposed upon (b)a foamed resin layer at least 5 mm (200 mil) thick. The aggregatedensity of layer (b) is preferably in the range 0.5 to 10.0. For ananimal stall floor covering, it is stated that layer (a) is preferably0.5 to 5 mm (20 to 200 mil) thick and layer (b) is preferably at least20 mm (800 mil) thick.

DISCLOSURE OF THE INVENTION

The present invention provides a resilient floor covering whichcomprises a polymer composition wear layer and is characterised in thatthe polymer composition wear layer comprises an ionomer resin and apolyfunctional polymerisable olefinic compound. In one embodiment of theinvention the wear layer is transparent or translucent and overlies adecorative layer, which can be seen through the wear layer. In anotherembodiment of the invention, the wear layer comprises a small proportionof coloured particles and is accordingly opaque.

The invention further provides a method of manufacturing a resilientfloor covering including the step of laminating a wear layer to one ormore underlying layers and characterised in that the wear layer is apolymer composition film which comprises an ionomer resin and apolyfunctional polymerisable olefinic compound.

MODES FOR CARRYING OUT THE INVENTION

The ionomer resin is a thermoplastic copolymer based on an olefin and analpha,beta-unsaturated carboxylic acid, in which the carboxylic acidgroups are at least partially neutralised by salt formation with a metalcation. The olefin may for example be propylene or preferably ethylene.The alpha,beta-unsaturated carboxylic acid may for example be acrylicacid or preferably methacrylic acid. The copolymer may in addition bebased on smaller amounts of one or more other polymerisable olefinicmonomers, for example esters of acrylic or methacrylic acid. The metalcation may for example be lithium, sodium or preferably zinc.Zinc-containing ionomer resins have been found to give good abrasionresistance in the floor coverings of the invention. Mixtures of two ormore olefins and/or alpha, beta-unsaturated carboxylic acids and/ormetal cations may be used. The wear layer of the floor coverings of theinvention may comprise a single grade of resin or a blend of two or moregrades of resin to provide the desired balance of properties.

The polyfunctional polymerisable olefinic compound is preferably apolyfunctional acrylic ester, for example a glycol diacrylate ortrimethylolpropane triacrylate, or more preferably a polyfunctionalmethacrylic ester, for example a glycol dimethacrylate or in particulartrimethylolpropane trimethacrylate. Mixtures of polyfunctionalpolymerisable olefinic compounds may be used, including mixtures ofcompounds of different structures. It has been found that the presenceof such compounds in the wear layer provides improved cigarette burnresistance. It has further been found that such methacrylate esters mayprovide processing advantages over the corresponding acrylate estersduring the manufacture of floor coverings according to the invention, aswill be explained more particularly hereinafter. The polymer compositionwear layer of the floor coverings of the invention may contain a smallproportion of one or more substances known as initiators for thepolymerisation of the olefinic compound, for example organic peroxides.The polymer composition wear layer may comprise 10 to 50 parts by weightof the polyfunctional polymerisable olefinic compound per 100 parts byweight ionomer resin (parts per hundred, phr), preferably 10 to 30 phr.

The polymer composition wear layer of the floor coverings of theinvention is preferably essentially free from substances of the classknown as simple ester plasticisers. These substances are known asplasticisers for PVC, and they include for example high-boiling alkylphthalic and phosphoric esters. Such plasticisers have been found toexude (bleed) from ionomer resin films, and in consequence wear layerscontaining significant proportions of such plasticisers may be found tobe undesirably slippery.

The polymer composition wear layer of the floor coverings of theinvention may optionally contain hard particles, for example syntheticresin particles, to improve wear properties and slip resistance.

The polymer composition wear layer of the floor coverings of theinvention may comprise one or more coloured dyestuffs. An opaque polymercomposition wear layer may comprise about 0.1 to about 10, often about 1to about 5, percent by weight of coloured particles such as pigments anddyed or pigmented fibres or flakes. Such an opaque polymer compositionpreferably includes little or no filler.

The polymer composition wear layer may consist essentially of theionomer resin and the polyfunctional polymerisable olefinic compound,optionally together with such hard particles and/or such colouredmaterial.

The thickness of the wear layer of the floor coverings of the inventionis preferably in the range 50 to 1000 micron, more preferably 250 to 750micron. The polymer composition wear layer of the floor covering of theinvention may be formed by powder coating or dispersion coating but itis preferably an extruded or calendered film, more preferably anextruded film. The wear layer may consist of a single film or of two ormore such films laminated together. If two or more films are used, suchfilms may be the same or different. The upper surface of the wear layermay be embossed.

When the wear layer is transparent or translucent, the decorative layerof the floor coverings of the invention may be printed with a decorativepattern, which may be preferred, or may be a solid-coloured layer. Whena printed layer is used it may be based on any suitable type ofprintable transparent film, for example an acrylic or ionomer film. Thethickness of this film is preferably in the range 25 to 125 micron. Sucha printed patterned layer is preferably based on an extruded film. Theprinted side of the printed patterned layer may be disposed towards oraway from the wear layer. When a solid-coloured layer is used, it may bebased on a film as described hereinbefore for a printed layer or it maybe a solid-coloured face ply layer as described hereinafter.

The polymer composition wear layer and the decorative layer require tobe bonded (laminated) together. The surfaces to be bonded together maybe activated beforehand, for example by exposure to a corona dischargeor flame treatment. In one embodiment of the method of the invention,the wear layer and the decorative layer are bonded together by hot(thermal) lamination. This embodiment may be generally satisfactory whenthe decorative layer is an ionomer film but may be less satisfactory inother cases. In another embodiment of the method of the invention, thewear layer and the decorative layer are bonded together by means of anadhesive interlayer. Use of such an adhesive interlayer is generallypreferred when the decorative layer is not an ionomer film but is forexample an acrylic film.

In one version of this latter embodiment, the adhesive interlayer is athin layer of a suitable liquid adhesive, for example a liquid urethaneadhesive. A liquid urethane adhesive is preferably based on an aliphaticisocyanate, because such urethane adhesives have good clarity andpossess good resistance to yellowing when exposed to UV light. Theadhesive layer is preferably as thin as possible consistent with theformation of a uniform bond between the wear layer and the decorativelayer. The adhesive layer is generally applied at a rate of about 5 to50 g/m² (dry film weight), corresponding to a thickness of about 4 to 40micron.

In another version of this latter embodiment, the adhesive interlayer isan extruded film having good lamination and adhesion properties both tothe ionomer resin wear layer and to the decorative layer. The extrudedinterlayer film is preferably as thin as possible consistent with easeof manufacture and with good lamination properties, and it is generallyno more than about 75 micron thick, preferably no more than about 50micron thick, more preferably no more than about 25 micron thick. Theextruded interlayer film may for example be an extruded polyurethanefilm, and it is preferably a co-extruded film containing a layer ofpolyethylene or similar material bonded to a layer of polyurethane. Uponlamination, the polyethylene layer bonds well to the ionomer resin layerand the polyurethane layer bonds well to the acrylic layer. Thepolyurethane is preferably based on an aliphatic isocyanate to providegood clarity and resistance to UV light.

In a further alternative embodiment of the method of the invention, aco-extruded film consisting of a polymer composition layer and anadhesive layer is used. The adhesive layer may for example be apolyurethane layer, preferably an aliphatic polyurethane. The polymercomposition layer serves to provide the wear layer in the floor coveringas described hereinabove. The adhesive layer is adhered to thedecorative layer by hot lamination. The adhesive layer is preferably nomore than about 50 micron thick, more preferably no more than about 25micron thick.

It is thought that thermal processing, for example extrusion and hotlamination, initially induces some degree of grafting of thepolyfunctional olefinic compound onto the ionomer resin, andsubsequently induces crosslinking. It is further thought that thisgrafting and crosslinking may be the origin of the good cigarette burnresistance generally observed in the floor coverings of the invention.It has surprisingly and advantageously been found that in general it isnot necessary to take special steps to induce polymerisation of thepolymerisable olefinic compound during the manufacture of the floorcoverings of the invention, especially if it is a methacrylate ester.For example, it is known that polymerisation of such polymerisableolefinic compounds can be initiated or accelerated by exposure toactinic radiation, for example UV light or an electron beam. The methodof the invention preferably does not include the step of exposing thefloor covering to actinic radiation.

The polymer composition wear layer may be manufactured by reactiveextrusion, in which the ionomer resin is extruded through an extruderinto which the polymerisable olefinic compound is injected. Care shouldbe taken to avoid excessive reaction in the extruder, as this may leadto early crosslinking and consequent difficulties in processing. Careshould also be taken to ensure that some reaction takes place in theextruder, otherwise the olefinic compound may exude from the extrudedsheet at the point of extrusion or on storage. The degree of reaction inthe extruder may readily be controlled by suitable variation oftemperature, residence time, olefinic compound, injection point,proportion of polymerisation initiator in the composition, and the like.Further reaction can be induced by thermal treatment subsequent toextrusion, for example calendering, or by exposure to microwave or IRradiation.

Especially when the wear layer is transparent or translucent, the floorcoverings of the invention preferably comprise a face ply layer adjacentto the decorative, preferably printed patterned, layer on the sideremote from the wear layer. The face ply layer is preferably acalendered or extruded film. The material of the face ply layer isgenerally a thermoplastic polymer resin filled with a filler such ascalcium carbonate or hydrated aluminium oxide. The material mayadditionally comprise a pigment such as a white pigment, for exampletitanium dioxide, for example at about 10 parts by weight per 100 partspolymer resin. The polymer resin preferably contains no chlorine.Examples of suitable polymer resins include ethylene/vinyl acetate andethylene/alkyl acrylate, for example methyl or butyl acrylate,copolymers. The face ply layer composition may additionally comprise oneor more lubricants, for example stearic acid.

The face ply layer composition may additionally comprise a smallproportion of a binder polymer such as an ethylene/alkyl acrylate/maleicanhydride terpolymer, for example about 5 to about 10 parts by weight ofthe binder polymer per 100 parts by weight of the polymer resin (partsper hundred, phr). In the absence of such a binder polymer, thepractical maximum proportion of a filler such as calcium carbonate maybe found to be about 250 or 270 phr. If higher proportions of filler areused, the mechanical properties (for example strength and resistance tocracking) of the face ply layer are adversely affected. When such abinder polymer is present in the composition, it has been found thathigher proportions of the filler can be used. This is advantageous inthat the filler is generally less expensive than the polymer resin.Furthermore, high levels of filler in the face ply layer provide adesirably high degree of opacity. Still further, such binder polymersmay serve to promote adhesion of the face ply to adjacent layers in thefloor covering. It has been found that if the proportion of the binderpolymer is higher than about 10 phr, the face ply layer composition andfilms made therefrom may be difficult to process; for example, they maytend to stick to hot rollers.

It may be desirable to interpose an adhesive interlayer between thedecorative, preferably printed patterned, layer and the face ply layer.This adhesive interlayer may be a liquid adhesive or an extruded orco-extruded film, for example as described hereinabove. It may beadvantageous to activate the surface of the decorative, preferablyprinted patterned, layer or the face ply layer or both to improveadhesion, for example by corona discharge or flame treatment.

The floor covering of the invention may alternatively comprise a faceply layer of the type hereinbefore described serving as the decorativelayer adjacent to the wear layer. In such a case, the face ply layergenerally contains one or more coloured pigments. Adhesion between thewear layer and the decorative layer may be improved by use of surfacetreatment and/or an adhesive interlayer.

The floor coverings of the invention preferably additionally comprise abacking (lower) layer. The backing layer is preferably a calendered orextruded film. The material of the backing layer is generally athermoplastic polymer resin filled with a filler such as calciumcarbonate or hydrated aluminium oxide and preferably additionallycontaining a black pigment such as carbon black, for example about 1 to3 phr carbon black. In general, the backing layer may contain about 10to about 400 phr filler. The polymer resin preferably contains nochlorine. Examples of suitable polymer resins include ethylene/vinylacetate and ethylene/alkyl acrylate, for example methyl or butylacrylate, copolymers. The backing layer composition may additionallycomprise one or more lubricants, for example stearic acid. The amount offiller is chosen to provide a floor covering which has a low tendency tocurl. For example, the backing layer composition may contain about 100to about 150 phr calcium carbonate. The backing layer preferably has aroughened lower surface. For example, it may be imprinted with thepattern of a canvas mesh belt.

The floor coverings of the invention may additionally comprise a foamlayer, for example a polyurethane foam layer, above the backing layer.Such floor coverings are known as cushion flooring.

The floor coverings of the invention as a whole preferably containessentially no chlorine.

The floor coverings of the invention may be manufactured by hotlamination of all the individual films between heated rollers in amulti-stage or preferably a single-stage operation. The laminationtemperature depends to some extent on the nature of the materials ofwhich the films are composed, but it may generally be in the range 120°to 170° C. The floor coverings may alternatively be manufactured byother known methods, for example compression moulding. Particularly whenthe wear layer is transparent or translucent and the decorative layer isa solid-coloured layer or when the wear layer is opaque, the floorcoverings may be made by co-extrusion.

A particularly preferred form of construction for a floor coveringaccording to the invention is a laminate of films in the followingsequential order, optionally separated by adhesive interlayers asdescribed hereinabove:

(1) extruded polymer composition film containing or consistingessentially of an ionomer resin and a polyfunctional polymerisableolefinic compound such as trimethylolpropane trimethacrylate (TMPTMA);

(2) printed patterned layer as decorative layer;

(3) face ply layer; and

(4) backing layer.

The floor coverings of the invention possess excellent resistance toabrasion, scratching, scuffing, indentation and staining. They possessgood burn resistance, for example when a lit cigarette is stubbed out onthe wear layer or allowed to smoulder on the wear layer. They containvery low amounts of volatile organic materials. They possess excellentoptical clarity, are free from yellowness and resist yellowing whenexposed to the normal amounts of UV light encountered in interiorenvironments. The visual appearance of a decorative layer, preferablyhaving a printed pattern, through a transparent or translucent wearlayer in the floor coverings of the invention is considerably more clearand less dull in comparison with the appearance of the printed patternin conventional vinyl floor coverings. The floor coverings of theinvention may be used in sheet or tile form.

The invention is illustrated by the following Examples, in which partsand proportions are by weight unless otherwise specified:

EXAMPLE 1

A floor tile was prepared by laminating together the following sequenceof films:

(1) extruded ionomer resin composition film 150 micron thick, in whichthe ionomer resin was a zinc-containing ionomer resin available from DuPont under the Trade Mark "Surlyn 9910", and the composition contained15 parts trimethylolpropane trimethacrylate (TMPTMA) per 100 partsionomer resin;

(2) ionomer resin film as (1);

(3) ionomer resin film as (1) except that it was 75 micron thick;

(4) extruded acrylic film 75 micron thick printed with a decorativepattern;

(5) face ply 1 mm thick consisting of 100 parts ethylene/methyl acrylatecopolymer resin available from Elf Atochem under the Trade Mark "Lotryl18MA02", 5 parts ethylene/acrylic ester/maleic anhydride terpolymerbinder resin available from Elf Atochem under the Trade Mark "Lotader4700", 275 parts calcium carbonate as filler, and 10 parts titaniumdioxide as white pigment.

(6) backing layer 1 mm thick consisting of 100 parts Lotryl 18MA02, 135parts calcium carbonate as filler and 2 parts carbon black.

The surface of (3) to be bonded to (4) and the surface of (4) to bebonded to (5) were subjected to corona discharge so that the surfacetension of the treated surface assessed by measuring the spreading ofcoloured inks was at least 40 dynecm⁻¹. The treated surfaces were coatedwith 25 g/m² dry film weight of a liquid aliphatic urethane adhesivebefore lamination. The films were laminated together by passage at aspeed of 4 m/min between rollers heated to 130° C., and the resultinglaminate was passed over chill rollers and collected on a reel.

The tile produced had the following properties, measured according toBritish Standard 3261 where applicable, compared with those of acommercial resilient vinyl floor tile:

    ______________________________________                                                         Ionomer                                                                       Resin   PVC                                                  ______________________________________                                        Taber abrasion     0.03      0.19                                             (weight loss g/1000 cycles)                                                   Taber scratch (g/1.25 mm)                                                                        500       500                                              Curl               Pass      Pass                                             Ply adhesion       Pass      Pass                                             Elastic product (Nm.sup.-2)                                                                      12        15                                               Residual indentation (micron)                                                                    0         50                                               Scuff resistance   Better    Standard                                         Staining -- curry powder                                                                         B         D                                                Staining -- boot polish                                                                          B         D                                                Clarity            Better    Standard                                         UV resistance      Better    Standard                                         ______________________________________                                    

In the Taber scratch test, the ionomer resin surface was merely marked,but material was removed from the surface of the PVC. Residualindentation was measured to the nearest thousandth of an inch (25micron). Staining was assessed on a scale of A (no stain) to E (badlystained).

EXAMPLE 2

Ionomer resin (Surlyn 9910) was worked in a calender mill in which theroll temperatures were 165°-170° C. and 145°-150° C. The rollers werecoated with a small amount of a lubricant to prevent sticking. Differentknown amounts of trimethylolpropane trimethacrylate (TMPTMA) weredrip-fed into the molten mass which was then removed from the rolls inthe form of a clear film approximately 0.5 mm thick, suitable for use asthe wear layer of a resilient floor tile. The properties of the filmswere assessed and the following results obtained:

    ______________________________________                                                                Taber    Taber                                              TMPTMA   Shore D  Abrasion Scratch Coin                                 Sample                                                                              phr      Hardness g/1000 cycles                                                                          mm @ 500 g                                                                            Scratch                              ______________________________________                                        A     0        51.5     0.026    1.52    superb                               B     10       54.0     0.022    1.65    superb                               C     15       55.5     0.034    1.27    superb                               D     20       56.5     0.031    1.52    superb                               E     30       55.5     0.031    1.91    superb                               F     40       63.0     0.079    1.91    superb                               ______________________________________                                    

The amount of TMPTMA is expressed as parts per 100 parts ionomer resin.The Taber Scratch measurement was that of scratch width at the specifiedloading. In samples A and B, the surface was only lightly marked,whereas in samples C-F marking was more severe with some loss ofmaterial from the surface. The samples with higher levels of TMPTMA hada much harder feel than that of the control, and sample F was relativelybrittle.

The films were optionally exposed to electron beam radiation (6 Mrad),and the cigarette burn properties (stub test) of the untreated andtreated samples were assessed. The following results were obtained:

    ______________________________________                                        Sample    Untreated      Electron-beam treated                                ______________________________________                                        A         Poor, black    Similar to untreated,                                          charring. Very but charring less                                              similar to standard                                                                          noticeable.                                                    formulation PVC.                                                    B         Area of degradation                                                                          Similar to untreated                                           similar to A,                                                                 although smaller                                                              area of charring,                                                             approx. 50% of                                                                damaged area.                                                                 Remaining area                                                                translucent.                                                        C         Area of degradation                                                                          Similar to untreated                                           similar to A but                                                              less charring,                                                                approx. 25% of                                                                damaged area.                                                                 Remaining area                                                                translucent.                                                        D         Similar to C   Similar to untreated                                 E         Area of degradation                                                                          Not tested                                                     slightly less than                                                            A, but very little                                                            charring. Good                                                                result.                                                             F         Area of degradation                                                                          Not tested                                                     further reduced,                                                              practically no                                                                charring. Very good                                                           result.                                                             ______________________________________                                    

It will be observed that exposure to electron-beam radiation madeessentially no difference to cigarette burn resistance.

Samples of D and E (which had not been exposed to the electron beamtreatment) were conditioned at 165° C. for up to 120 minutes. For sampleD, cigarette burn resistance improved considerably after 30 or 60minutes' conditioning, without any change in film colour. After longerconditioning, no further improvement in cigarette burn resistance wasobserved, and there was some degree of yellowing. For sample E,cigarette burn resistance was improved by 30 minutes' conditioningwithout any change in colour. No further improvement was noted after 60minutes and some yellowness was evident.

We claim:
 1. A resilient floor covering comprising a polymer compositionwear layer laminated to at least one underlying layer, wherein saidpolymer composition wear layer comprises a polymerization product ofa)an ionomer resin which is the co-polymerization product ofα,β-unsaturated carboxylic acid and an olefin, wherein the carboxylicacid groups of said acid are at least partially neutralized by saltformation with metal ions; and b) a polyfunctional polymerizableolefinic compound.
 2. The floor covering of claim 1, wherein saidpolyfunctional polymerizable olefinic compound consists essentially ofat least one compound selected from the group consisting ofpolyfunctional acrylic esters and polyfunctional methacrylic esters. 3.The floor covering of claim 2, wherein said polyfunctional polymerizableolefinic compound consists essentially of trimethylolpropanetrimethacrylate.
 4. The floor covering of claim 1, wherein saidpolyfunctional polymerizable olefinic compound is present in saidpolymer composition in an amount of 10 to 50 parts by weight per 100parts by weight of said ionomer resin.
 5. The floor covering of claim 4,wherein said polyfunctional polymerizable olefinic compound is presentin said polymer composition in an amount of 10 to 30 parts by weight per100 parts by weight of said ionomer resin.
 6. The floor covering ofclaim 1, wherein said polymer composition wear layer is in the form ofat least one extruded film.
 7. The floor covering of claim 1, whereinthe thickness of said wear layer is in the range of 50 to 1000 microns.8. The floor covering of claim 7, wherein the thickness of said wearlayer is in the range of 250 to 750 microns.
 9. The floor covering ofclaim 1, wherein said polymer composition wear layer is transparent andoverlies a decorative layer.
 10. The floor covering of claim 1, whereinsaid polymer composition wear layer is translucent and overlies adecorative layer.
 11. The floor covering of claim 9, comprising alaminate of films in the following sequential order:a) as said wearlayer, at least one extruded polymer composition film which comprisesthe polymerization product of said ionomer resin and said polyfunctionalpolymerizable olefinic compound; b) as said decorative layer, a printedpatterned layer; c) a face ply layer; and d) a backing layer.
 12. Thefloor covering of claim 11, wherein said polymer composition is anopaque composition which further contains 0.1 to 10 percent coloredparticles by weight of said composition.
 13. The resilient floorcovering of claim 1, wherein said floor covering additionally comprisesa face ply layer, said face ply layer comprising a composition whichcomprises a thermoplastic polymer resin, a filler and a binder polymer.14. The resilient floor covering of claim 13, wherein said thermoplasticpolymer resin is selected from the group consisting of ethylene/vinylacetate copolymers and ethylene/alkyl acrylate copolymers.
 15. Theresilient floor covering of claim 13, wherein said binder polymer is anethylene/alkyl acrylate/maleic anhydride terpolymer.
 16. The resilientfloor covering of claim 13, wherein said binder polymer is present insaid composition in an amount of 5 to 10 parts by weight per 100 partsby weight of said thermoplastic polymer resin.
 17. The resilient floorcovering of claim 13, wherein a filler is present in said composition inan amount of at least 250 parts by weight per 100 parts by weight ofsaid thermoplastic polymer resin.
 18. A method of manufacturing theresilient floor covering of claim 11, comprising the step of laminatingsaid wear layer to said at least one underlying layer, wherein said wearlayer is in the form of at least one film made from said polymerizationproduct.
 19. The method of claim 18, wherein the polyfunctionalpolymerizable olefinic compound present in said polymerization productis adapted to be cured by thermal processing without exposure to actinicradiation.
 20. The method of claim 18, wherein layers arranged in thefollowing sequence:a) as said wear layer, at least one extruded polymercomposition film which comprises the polymerization product of saidionomer resin and said polyfunctional polymerizable olefinic compound;b) a decorative printed patterned layer; c) a face ply layer; and d) abacking layerare thermally laminated together in a single-stage process,thereby forming said floor covering.
 21. The method of claim 18, whereinsaid floor covering additionally comprises at least one adhesiveinterlayer disposed between at least one adjacent pair of layers.